Over the last decades numerous investigations in various areas have devoted special attention to a group of crystalline aluminosilicates known as zeolites, which have a negative surface charge that allows the exchange of cations, whose basic structure is formed by a three-dimensional regular arrangement of AlO4− and SiO4− belonging to the tectosilicates group, which give rise to a system of intercommunicated polyhedral cavities that determine the micro porosity of these materials. This derives into diverse applications of this mineral used commercially as ion exchanger, selective adsorbent, dehydrator, molecular sieve, and catalyst.
Because the zeolites do not contaminate nor cause adverse effects to human or animal health, they are so harmless that they are added to various environmental processes for the elimination, adsorption and immobilization of heavy metals, inorganic as well as organic compounds, in addition to the removal of radioactive elements, purification and treatment of water and treatment of sludge, in the petrochemical and mining industry to treat liquid industrial residues, as well as to control spills and extraction of mining acid spills, as supports for catalysts, in industry and agronomy, animal nutrition and health, agriculture, etc.
Considering the adsorption characteristics presented by these materials, they have been reported as selective containers for various substances.
However, if magnetic properties are incorporated in the zeolites by means of a coating, increasing their magnetic susceptibility, their use for the elimination of contaminants would be expanded, as well as a means for controlled delivery of drugs, genes, proteins, antigens, and other molecules.
All this leads us to propose that the characteristics of the zeolites when coated with magnetic iron particles would enhance their use in many areas.